A method for producing low aromatic white oil

Abstract

A method for producing low-aromatic white oil involves the mercapto-olefin addition reaction of a nickel mercaptonicate complex with methylallyltri-n-butyltin and vinyl ferrocene, respectively, using a carbon molecular sieve as a support to prepare a hydrogenation catalyst. This catalyst exhibits good mass transfer performance, inhibiting cracking reactions and pore blockage. The porous structure of the carbon molecular sieve provides effective channels for hydrogen atoms to diffuse on and within the catalyst surface, thereby improving hydrogen utilization. Dispersing nickel metal ions on the support surface to form a monolayer or multilayer structure enhances catalyst activity. It also resists the influence of some harmful substances on catalyst activity. The hydrogenation catalyst prepared by this invention enhances catalyst stability, reduces sintering and deactivation rates, thereby extending catalyst life. Furthermore, it contributes to improving the efficiency and selectivity of the hydrocracking process.

Description

Technical Field

[0001] This invention relates to the field of low-aromatic white oil technology, and particularly to a method for producing low-aromatic white oil. Background Art

[0002] White oil is a colorless, odorless, and non-corrosive special mineral oil obtained through deep refining to remove impurities such as aromatics, oxygen, sulfur, and nitrogen. It belongs to the lubricating oil fraction. White oil is primarily composed of saturated hydrocarbons, with extremely low levels of aromatics, nitrogen, oxygen, and sulfur. It possesses excellent chemical inertness and superior light and thermal stability, making it widely applicable. In China, white oil is classified into three categories: industrial white oil, cosmetic white oil, and food-grade white oil. Industrial white oil is mainly used in the chemical fiber, aluminum processing, and rubber industries, and is also used for lubrication of textile machinery, precision instruments, and compressor sealing oils.

[0003] Chinese Patent CN113372951A discloses a method for producing low-aromatic white oil, comprising the following steps: (a) heating the raw material vacuum wax oil to remove impurities and desulfurize; (b) desulfurization: heating the pretreated raw material vacuum wax oil and sending it to a high-pressure stripping tower for desulfurization to obtain a first reaction oil; (c) cracking and dewaxing: the first reaction oil and circulating hydrogen enter a second reactor for cracking and dewaxing to obtain a second reaction oil; (d) catalytic saturation: the second reaction oil enters a third reactor, where a metal catalyst is added to react with hydrogen, saturating the polycyclic aromatic hydrocarbons to obtain a catalytic oil; (e) vacuum distillation: the catalytic oil is subjected to vacuum distillation and fractionation to obtain a food-grade white oil product.

[0004] Chinese Patent CN107937024B discloses a method for producing high-quality light white oil from base oil, comprising the following steps: the raw base oil is heated to the reaction temperature and then fully mixed with hydrogen, and then enters a hydrotreating reactor carrying catalyst I. Under the action of hydrotreating catalyst I, a hydrotreating reaction is carried out to remove most of the S, N, and aromatic impurities in the raw base oil; the reaction product enters two reactors connected in series carrying catalysts II and III respectively, and contacts catalysts II and III to carry out a saturated reaction for desaturation and dearomatics removal; the obtained reactants are separated into gas and liquid by high- and low-pressure separators and then enter a fractionation system for fine cutting to obtain various grades of high-quality light white oil products.

[0005] Chinese Patent CN215250645U discloses a production apparatus for low-aromatic white oil, comprising a combustion furnace, a first reactor, a high-pressure stripping tower, a feed pump, a second reactor, a fractionation system, and a product discharge device connected in series via pipelines. A hydrogen input pipeline is connected between the feed pump and the second reactor. A third reactor is provided between the second reactor and the fractionation system. The outlet of the second reactor is connected to the inlet of the third reactor, and the outlet of the third reactor is connected to the inlet of the fractionation system. The third reactor is provided with a packing zone containing at least one precious metal catalyst.

[0006] The white oil prepared by the above patents and existing technologies has a high aromatic content and uses a precious metal catalyst in the reaction. The precious metal catalyst is mainly a precious metal Pt or Pb supported on a molecular sieve. However, due to the high price of precious metals, the production cost of the catalyst is too high. In addition, precious metals are very sensitive to impurities such as S, N, and Cl, which can easily cause catalyst deactivation. Summary of the Invention

[0007] To overcome the technical problems of high aromatic content and high catalyst cost in white oil prepared by existing technologies, this invention proposes a method for producing low aromatic white oil.

[0008] The specific process of this invention is as follows:

[0009] H1: Hydrocracking tail oil, along with fresh hydrogen and recycled hydrogen, enters the first reactor and the second reactor;

[0010] H2: After the reaction is complete, it enters the first separator for gas-liquid separation, and the liquid phase enters the second separator for further gas-liquid separation;

[0011] H3: The separated oil fraction is subjected to vacuum distillation to obtain low-aromatic white oil.

[0012] A further technical solution of the present invention is: the hydrogen-to-oil volume ratio is 500-800:1.

[0013] A further technical solution of the present invention is that the reaction temperature is 280-380℃.

[0014] A further technical solution of the present invention is that the reaction pressure is 12-16 MPa.

[0015] A further technical solution of the present invention is: the airspeed is 0.8-1.2h. -1 .

[0016] A further technical solution of the present invention is: the method for preparing the hydrogenation catalyst in the first reactor and the second reactor is as follows:

[0017] K1: Add 16-32 parts by weight of nickel nitrate, 1000-1200 parts by weight of DMF and 15-30 parts by weight of 4-mercaptonicotinic acid to a sealed reactor, react at 60-80℃ for 120-150 min, and then cool to room temperature after the reaction.

[0018] K2: Then add 1-5 parts of methylallyltri-n-butyltin, 0.001-0.05 parts of vinyl ferrocene, and 2-5 parts of triethanolamine. Stir and react at 50-60℃ for 140-200 min, then stir for 20-50 min to form a nickel organometallic impregnation solution.

[0019] K3: Then add 100-200 parts of carbon molecular sieve to the nickel organometallic impregnation solution, stir and react at 50-70℃ for 10-20h, then add 30-40 parts of sodium borohydride, stir and react for 10-20h, filter and dry after completion.

[0020] K4: In a hydrogen atmosphere, maintain at 100-120℃ for 50-80 minutes; after cooling to room temperature, purge with inert gas to obtain the finished hydrogenation catalyst.

[0021] A further technical solution of the present invention is that the carbon molecular sieve is one of the commercially available products CMS220 carbon molecular sieve, CMS240 carbon molecular sieve, and CMS260 carbon molecular sieve.

[0022] The principle of hydrogenation catalyst preparation in the reactor is as follows:

[0023] Nickel nitrate reacts with 4-mercaptonicotinic acid to form a nickel mercaptonicotinate complex; the nickel mercaptonicotinate complex undergoes mercapto-olefin addition reactions with methylallyltri-n-butyltin and vinyl ferrocene, respectively; carbon molecular sieve is used as a support, and the catalyst is obtained by reduction with sodium borohydride and then by reduction with hydrogen.

[0024] The present invention provides a method for producing low-aromatic white oil, which, compared with the prior art, has the following significant advantages:

[0025] 1. The method for producing low-aromatic white oil of the present invention can greatly reduce the aromatic content in white oil;

[0026] 2. The catalyst used in this invention greatly reduces production costs and will not lose its activity due to poisoning by impurities such as S, N, and Cl.

[0027] 3. This invention utilizes a nickel mercaptonicotin complex to perform mercapto-olefin addition reactions with methylallyltri-n-butyltin and vinyl ferrocene, respectively. A hydrogenation catalyst prepared using carbon molecular sieves as a support exhibits good mass transfer performance, inhibiting cracking reactions and pore blockage. The porous structure of the carbon molecular sieve provides effective channels for hydrogen atom diffusion on and within the catalyst surface, thereby improving hydrogen utilization. Dispersing nickel metal ions on the support surface to form a monolayer or multilayer structure enhances catalyst activity and resists the effects of harmful substances (such as sulfur, nitrogen, and oxygen) on catalyst activity. Furthermore, the carbon molecular sieve can be further enhanced with surface modification to improve its anti-poisoning ability.

[0028] 4. The hydrogenation catalyst prepared by this invention can enhance the stability of the catalyst, reduce the rate of sintering and deactivation, thereby extending the catalyst life; it helps to improve the efficiency and selectivity of the hydrocracking process. Detailed Implementation

[0029] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. After reading the present invention, any modifications of the present invention in various equivalent forms by those skilled in the art will fall within the scope defined by the appended claims.

[0030] Example Test Method:

[0031] 1. The method for detecting aromatic hydrocarbon content shall refer to SH / T0966;

[0032] 2. The method for detecting ultraviolet absorbance is in accordance with GB / T11081.

[0033] Example 1

[0034] A method for producing low-aromatic white oil, comprising the following steps:

[0035] H1: Hydrocracking tail oil, along with fresh hydrogen and recycled hydrogen, enters the first reactor and the second reactor;

[0036] H2: After the reaction is complete, it enters the first separator for gas-liquid separation, and the liquid phase enters the second separator for further gas-liquid separation;

[0037] H3: The separated oil fraction is subjected to vacuum distillation to obtain low-aromatic white oil.

[0038] The hydrogen-to-oil volume ratio is 500:1.

[0039] The reaction temperature is 280℃.

[0040] The reaction pressure is 12 MPa.

[0041] Airspeed is 0.8h -1.

[0042] The method for preparing the hydrogenation catalyst in the first and second reactors is as follows:

[0043] K1: Add 16g of nickel nitrate, 1000g of DMF, and 15g of 4-mercaptonicotinic acid to a sealed reaction vessel, react at 60℃ for 120min, and then cool to room temperature after the reaction is complete;

[0044] K2: Then add 1g of methylallyltri-n-butyltin, 0.001g of vinyl ferrocene, and 2g of triethanolamine. Stir and react at 50°C for 140 min, then stir for 20 min to form a nickel organometallic impregnation solution.

[0045] K3: Then add 100g of carbon molecular sieve to the nickel organometallic impregnation solution, stir and react at 50℃ for 10h, then add 30g of sodium borohydride, stir and react for 10h, filter and dry after completion;

[0046] K4: Hold at 100°C for 50 minutes in a hydrogen atmosphere; after cooling to room temperature, purge with an inert gas to obtain the hydrogenation catalyst product.

[0047] The carbon molecular sieve mentioned is the commercially available CMS220 carbon molecular sieve.

[0048] Example 2

[0049] A method for producing low-aromatic white oil, comprising the following steps:

[0050] H1: Hydrocracking tail oil, along with fresh hydrogen and recycled hydrogen, enters the first reactor and the second reactor;

[0051] H2: After the reaction is complete, it enters the first separator for gas-liquid separation, and the liquid phase enters the second separator for further gas-liquid separation;

[0052] H3: The separated oil fraction is subjected to vacuum distillation to obtain low-aromatic white oil.

[0053] The hydrogen-to-oil volume ratio is 600:1.

[0054] The reaction temperature is 320℃.

[0055] The reaction pressure is 13 MPa.

[0056] Airspeed is 0.9h -1 .

[0057] The method for preparing the hydrogenation catalyst in the first and second reactors is as follows:

[0058] K1: Add 22g of nickel nitrate, 1050g of DMF, and 20g of 4-mercaptonicotinic acid to a sealed reaction vessel, react at 65℃ for 130min, and then cool to room temperature after the reaction is complete;

[0059] K2: Then add 2g of methylallyltri-n-butyltin, 0.01g of vinyl ferrocene, and 3g of triethanolamine. Stir and react at 55°C for 160 min, then stir for 30 min to form a nickel organometallic impregnation solution.

[0060] K3: Then add 140g of carbon molecular sieve to the nickel organometallic impregnation solution, stir and react at 55℃ for 14h, then add 34g of sodium borohydride, stir and react for 14h, filter and dry after completion;

[0061] K4: In a hydrogen atmosphere, maintain at 105°C for 60 minutes; after cooling to room temperature, purge with inert gas to obtain the hydrogenation catalyst product.

[0062] The carbon molecular sieve mentioned is commercially available CMS240 carbon molecular sieve.

[0063] Example 3

[0064] A method for producing low-aromatic white oil, comprising the following steps:

[0065] H1: Hydrocracking tail oil, along with fresh hydrogen and recycled hydrogen, enters the first reactor and the second reactor;

[0066] H2: After the reaction is complete, it enters the first separator for gas-liquid separation, and the liquid phase enters the second separator for further gas-liquid separation;

[0067] H3: The separated oil fraction is subjected to vacuum distillation to obtain low-aromatic white oil.

[0068] The hydrogen-to-oil volume ratio is 700:1.

[0069] The reaction temperature is 360℃.

[0070] The reaction pressure is 15 MPa.

[0071] Airspeed is 1.1 h -1 .

[0072] The method for preparing the hydrogenation catalyst in the first and second reactors is as follows:

[0073] K1: Add 30g nickel nitrate, 1150g DMF, and 25g 4-mercaptonicotinic acid to a sealed reaction vessel, react at 75℃ for 140min, and then cool to room temperature after the reaction is complete;

[0074] K2: Then add 4g of methylallyltri-n-butyltin, 0.03g of vinyl ferrocene, and 4g of triethanolamine. Stir and react at 55°C for 180 min, then stir for 40 min to form a nickel organometallic impregnation solution.

[0075] K3: Then add 180g of carbon molecular sieve to the nickel organometallic impregnation solution, stir and react at 65℃ for 18h, then add 38g of sodium borohydride, stir and react for 18h, filter and dry after completion;

[0076] K4: In a hydrogen atmosphere, maintain at 115°C for 70 minutes; after cooling to room temperature, purge with inert gas to obtain the hydrogenation catalyst product.

[0077] The carbon molecular sieve mentioned is commercially available CMS240 carbon molecular sieve.

[0078] Example 4

[0079] A method for producing low-aromatic white oil, comprising the following steps:

[0080] H1: Hydrocracking tail oil, along with fresh hydrogen and recycled hydrogen, enters the first reactor and the second reactor;

[0081] H2: After the reaction is complete, it enters the first separator for gas-liquid separation, and the liquid phase enters the second separator for further gas-liquid separation;

[0082] H3: The separated oil fraction is subjected to vacuum distillation to obtain low-aromatic white oil.

[0083] The hydrogen-to-oil volume ratio is 800:1.

[0084] The reaction temperature is 380℃.

[0085] The reaction pressure is 16 MPa.

[0086] Airspeed is 1.2h -1 .

[0087] The method for preparing the hydrogenation catalyst in the first and second reactors is as follows:

[0088] K1: Add 32g of nickel nitrate, 1200g of DMF, and 30g of 4-mercaptonicotinic acid to a sealed reaction vessel, react at 80℃ for 150min, and then cool to room temperature after the reaction.

[0089] K2: Then add 5g of methylallyltri-n-butyltin, 0.05g of vinyl ferrocene, and 5g of triethanolamine. Stir and react at 60°C for 200 min, then stir for 50 min to form a nickel organometallic impregnation solution.

[0090] K3: Then add 200g of carbon molecular sieve to the nickel organometallic impregnation solution, stir and react at 70℃ for 20h, then add 40g of sodium borohydride, stir and react for 20h, filter and dry after completion;

[0091] K4: In a hydrogen atmosphere, maintain at 120°C for 80 minutes; after cooling to room temperature, purge with inert gas to obtain the hydrogenation catalyst product.

[0092] The carbon molecular sieve mentioned is the commercially available CMS260 carbon molecular sieve.

[0093] Comparative Example 1

[0094] In this example, except that 4-mercaptonicotinic acid is not added in step K1, everything else is the same as in Example 1.

[0095] Comparative Example 2

[0096] In this example, except that methylallyltri-n-butyltin is not added in step K2, everything else is the same as in Example 1.

[0097] Comparative Example 3

[0098] In this example, except that vinyl ferrocene is not added in step K2, everything else is the same as in Example 1.

[0099] Table 1. Test results of the white oil prepared according to the implementation scheme.

[0100]

[0101] By comparing the data from the above embodiments and comparative examples, the production method of low-aromatic white oil of the present invention can significantly reduce the aromatic content in white oil; the hydrogenation catalyst prepared by the present invention can enhance the stability of the catalyst, reduce the rate of sintering and deactivation, thereby extending the catalyst life; and help improve the efficiency and selectivity of the hydrocracking process.

[0102] The above is merely one specific embodiment of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial modifications made to the present invention using this concept shall be considered as infringing upon the scope of protection of the present invention. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for producing low-aromatic white oil, comprising the following steps: H1: Hydrocracking tail oil, along with fresh hydrogen and recycled hydrogen, enters the first reactor and the second reactor; H2: After the reaction is complete, it enters the first separator for gas-liquid separation, and the liquid phase enters the second separator for further gas-liquid separation. H3: The separated oil fraction is subjected to vacuum distillation to obtain low-aromatic white oil; The method for preparing the hydrogenation catalyst in the first and second reactors is as follows: K1: Add 16-32 parts by weight of nickel nitrate, 1000-1200 parts by weight of DMF and 15-30 parts by weight of 4-mercaptonicotinic acid to a sealed reactor, react at 60-80℃ for 120-150 min, and then cool to room temperature after the reaction. K2: Then add 1-5 parts of methylallyltri-n-butyltin, 0.001-0.05 parts of vinyl ferrocene, and 2-5 parts of triethanolamine. Stir and react at 50-60℃ for 140-200 min, then stir for 20-50 min to form a nickel organometallic impregnation solution. K3: Then add 100-200 parts of carbon molecular sieve to the nickel organometallic impregnation solution, stir and react at 50-70℃ for 10-20h, then add 30-40 parts of sodium borohydride, stir and react for 10-20h, filter and dry after completion. K4: In a hydrogen atmosphere, maintain at 100-120℃ for 50-80 minutes; after cooling to room temperature, purge with inert gas to obtain the finished hydrogenation catalyst.

2. The method for producing low-aromatic white oil according to claim 1, characterized in that: The hydrogen-to-oil volume ratio is 500-800:

1.

3. The method for producing low-aromatic white oil according to claim 1, characterized in that: The reaction temperature is 280-380℃.

4. The method for producing low-aromatic white oil according to claim 1, characterized in that: The reaction pressure is 12-16 MPa.

5. The method for producing low-aromatic white oil according to claim 1, characterized in that: Airspeed is 0.8-1.2 h. -1 .

6. The method for producing low-aromatic white oil according to claim 1, characterized in that: The carbon molecular sieve mentioned is one of the commercially available products CMS220 carbon molecular sieve, CMS240 carbon molecular sieve, and CMS260 carbon molecular sieve.

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